1) Field of the Invention
This invention relates to soil compacting methods, devices and systems and, more particularly, to methods, devices and systems for utilizing and/or increasing the load bearing capacity of soil.
2) Description of the Prior Art
Structural foundations are designed to transmit the weight of the structure to the underlying soil or rock, and serve as a basic supporting member. The foundation must be essentially unyielding, since one of the chief requirements is the minimization or elimination of settlement due to yielding of the soil under the applied loads.
Structural foundations are of two main types, namely, spread foundations and pilings. A spread foundation is a structural element designed to distribute a concentrated load to reduce the distributed pressure to an allowable level which can safely be supported by the soil thereunder.
When the soil at or below the level where the spread foundation would normally be placed is unsuitable, then the weight of the structure must be transferred to the soil at greater depths or to rock. Bearing piers or caissons are used for this purpose. Such piers can be friction piles, which are supported through skin friction in a manner well known in the art.
However, bearing pier foundations provide very little, if any, resistance to twisting loads applied to the foundation, since their primary purpose is to support vertical loads.
Therefore, it is an object of the present invention to provide a bearing pier type foundation that gives support for vertical loads, as well as the twisting loads.
Spread foundations are preferable because they are relatively inexpensive compared to piles. However, when the safe bearing capacity or bearing value of the soil is less than the pressure applied to the soil by the foundation, then the foundation must be made of piles, unless the soil can be stabilized. The most popular way to stabilize the soil is through compaction by vibrating devices or rollers.
Present methods of compacting loose grain soil can increase the load-bearing capacity of the soil substantially. However, under the present systems, compacting soil requires extensive amounts of machinery and considerable amount of time. Pile driving causes soil failure during installation with little to no compaction. Further, with pile foundations, the integrity of the pile can be compromised during installation due to the compressive forces applied to the pilings.
Therefore, it is an object of my invention to install pilings cheaper and more effectively than that in the prior art, while compacting the surrounding soils during the installation process.